1. Field of the Invention
The invention relates to a method of operating an apparatus by means of a solid-state processor which holds a plurality of selectable programmed routines, which apparatus is powered by an electric mains, and during a conditional operation controlling, within a limited volume of space, at least one physical parameter through a predetermined range of values in the case of a power failure during execution of a selected routine, said method comprising a plurality of subroutines for the salvage of identifier data associated wih said selected routine interrupted by said failure.
The invention also relates to an apparatus operated by a solid-state processor and powered by an electric mains in which during a conditional operation, within a predetermined volume of space, at least one physical parameter is controlled through a predetermined range of values, said processor holding a plurality of programmed routines, at least one of said routines being interruptable in case of power failure.
In general, the invention may be applied to all apparatus in which sequential programs are controlled by a solid-state processor and whose cost price does not justify the use of cyclic and permanent control means, for example domestic appliances such as laundry or dish-washing machines, cooking appliances etc.
2. Description of the Prior Art
In appliances, equipped with electromechanical programming devices, the instantaneous setting in the case of a power failure is preserved but in the case of appliances whose operation is controlled by a solid-state processor a power failure results in the destruction of the data identifying the program in progress; when the power-supply voltage is restored, this means that the program of the apparatus is restarted without knowing exactly which part of the program has already been carried out. This problem is overcome by providing the apparatus with a data-saving device to which the data necessary for the subsequent continuation of the program are transferred and in which they are stored as soon as a failure occurs.
French Patent Specification no. 2,297,273 describes an electronically controlled washing machine equipped with a data-saving device. If the power failure is brief (approximately 8 seconds) the program is continued at the point where it was interrupted, employing the saving data. If the interruption is longer an accummulator maintains the logic circuit in the state which it occupied at the instant of failure. When power is restored the memory devices are re-activated in the reset state.
However, in certain cases the use of the saved data for exactly reprogramming the apparatus at the point of the program where the power failure occurred may be undesirable for said apparatus or for objects to be treated by said apparatus. Indeed, the absence or incorrect value of certain physical parameters at the instant that power is restored, compared with the values which would normally occur, may sometimes impair a correct execution of the program. When proceeding as described in the event of a longer power failure, the user himself should select a new program when the power is restored.
U.S. Pat. No. 3,959,778 describes a device for salvaging processor data. When a power failure is detected during execution of a program, the data present in the main memory is transferred to a peripheral and non-volatile memory.
However, the device only comprises means for detecting a power failure, but does not comprise means for organizing the restarting process at the instant that power is restored.
It is an object of the invention to provide a method where the apparatus itself determines whether the interrupted programmed routine is to be stopped or continued when the power is restored and in case of continuation determined under which condition restarting may be effected.